In the related art, the backlight module generally includes a back plate 01, a plastic frame 02 connected with the back plate 01, a reflective sheet 03, a light guide plate 04, and an optical membrane kit 05 which are disposed in turn on the back plate 01, as shown in FIG. 1. Wherein the back plate 01 and the plastic frame 02 are connected generally in a clamping manner. Specifically, referring to FIG. 1, the plastic frame 02 has a convex hook 021 extending outwardly, and a slot 011 is opened at a place where the back plate 01 corresponds to the hook 021 of the plastic frame 02. When intended to be engaged, the hook 021 of the plastic frame 02 can fall into the slot 011 of the back plate 01, and the hook 021 of the plastic frame 02 can hook a side edge wall of the back plate 01, so as to achieve an object of fixing the plastic frame 02.
However, in the actual production process, this one-time engaging method may easily cause a problem that the plastic frame and the back plate are not engaged firmly. At the same time, due to limitations of the existing manufacturing process of the plastic frame 02 and the back plate 01, there is a larger tolerance range between a size of the slot 011 of the back plate 01 and a size of the hook 021 of the plastic frame 02. When the size of the hook 021 of the plastic frame 02 and the size of the slot 011 of the back plate 01 are not matched, poor engagement such as a difficult engagement or virtual engagement will occur, so as to reduce a yield of the backlight module and increase waste of various materials during rework.